Mechanical stoker.



No. 67I,555. Patented Apr. 9, |90l. l

A. HOFMANN.

MECHANICAL STUKEH (Application filed July 16, 1900,) (No ModeL) 2Sheets-Sheet l,

E 'Wm @frec @f7/fawn Wim M Mmfw No. 67|,555. Patented Apr. 9, ISN". A.HUFMANN.

MECHANICALSTOKER.

(Application tiled July 1B, 1900.) (N0 Md'J 2 shuts-sheet 2.

v/SSES UNITED STATES PATENT y QEEIcE.

' ALFRED HORMANN, oF KEMPTTAL, SWITZERLAND.

MECHANICAL sToKER.

sPEcIFIcATIoN forming part of Letters Patent No. 671,555, dated April e,Ieoi. Application filed July 16, 1900. Serial No. 23,758. (No model.)

T0 all whom it may concern:

Be it known that I, ALFRED HORMANN, engineer, a citizen of the Republicof Switzerland, residing at 376 Ziiricherstrasse, Kem pttal,Switzerland, have invented a certain new and useful Improvement inMechanical Stokers, (Case No. 1,) of which the following is a full,clear, concise, and'eXact description, reference being had to theaccompanying drawings, forming a part of this speciiication.

This invention relates to mechanical stokers adapted for the continuousintroduction of fuel by means .of an inclined double-chain grating. i

The invention has for its object to obtain a complete and almostsmokeless consumption of the fuel without excess of air and with anautomatic regulation of the feed of such fuel and air.

The improved stoker is adapted for steamgenerators, cooking apparatus,and other apparatus for the generation of steam or other gases underpressure.

One form of construction is shown in the accompanying drawings, inwhich- Figure l is a vertical longitudinal section of a steam-boilerprovided with theimproved stoker. Fig. 2 is a front elevation ofltthesame, and Fig. 3 is a section taken on th`e line A B of Fig. l.

The fuel in any convenient form is fed into l the hopper a, where it isacted upon by the two toothed rollers b, which reduce the larger piecesinto pieces of ordinary size. The reduced fuel falls automatically intothe opening of the measuring-cylinder c, which delivers it onto theinclined plane d, down .which it slides and is distributed-upon thechain grate c. In order to prevent pieces of fuel from rebounding fromthe incline when falling from the measuring-cylinder c, a suspendedhinged plate f is provided, which after the accumulation of a certainquantity of fuel on one side thereof opens and allows the latter toslide down to the grate e. When it reaches the grate, the fuel, withouta supply of air, is conducted down the highly-inclined plane of the saidgrate to the llowest Apoint g thereof, where it is supplied with air andignited. The air is prevented from passing from below through theforemost part of the grate by means of a plate z, without airholes,iixed below the grate and extending from the inlet to the point g. Fromthe point g the grate ascends a sharp incline, and during the passage ofthe fuel from g to 72 combustion takes place. The incolnpletelyburnedportions of the fuel are thrown back toward the point g by the toothedroller t', and the clinkers which are caked to lire-bars are loosened bythe bending of the chain or grate and are completely detached by thescraper k. By means of this continuous feed of fuel, together with thearrangement of hearth at the rear side of the double inclined grate, theflame is obliged to pass over the fuel in a direction opposite to thatof its travel, thereby gradually heating the same and at the same timeconsuming all the gases evolved.

For `this purpose a iiue is arranged over the grate, which is formed atthe top and at the sides by the walls of the fire-box, consisting offreproof material, and at the, under side by the grate itself. This fluebegins at the rear end of the grate, passes back over the grate, and isthen bent for leading into the boiler or other apparatus to be heated.If the mechanical stoker is to be applied to boilers of another typethan that shown in the drawings, a part of the said flue -may be formedby the boiler itself. In the case of tubular boilers, for instance, thetop of the flue may be formed by the slanting tubes and the partitions.

To admit of tiring by hand during the stopping of the transmission shaftor during breakdowns, the sliding plane 0l is elevated by means of thelevers l and m and the fuel is introduced in the usual manner for [iatgrates through an opening o.

By lifting the inclined plane or iiap d, and thus causing it to swingaround its'fnlcrum p, the sectional area of the fire-flue is reduced andthe draft is reduced to the minim u-m, so that when opening theflre-door--t`. e., when stoking by handcold air is not drawn in.

The speed of travel of the fuel can be regulated within certain limitsand can be so adjusted as to supply the quantity of fuel so as toconfine the combustion to a portion only of the distance g h or toextend it over the whole length. At the same time with the alteration inthe speed of travel of the fuel IOO liaps will be opened or all will beclosed when no steam is required. This enables a variable eective areaof grate to be obtained to correspond to the direct consumption of fuel,while an excess of cold air, and consequent cooling of the gases and ofthe boiler, is prevented.

` The apparatus for regulating the speed of the arrangement consists ofa small steamcylinder r, with piston, which latter is acted upon by thesteam from' the boiler at Vthe lowerside, and by a counter-poise s ofslightlyless weight than the steam-pressure at' the top. An increase ofpressure in the boiler causes t'he piston with its counterpoise toascend and to again descend by the action of the latter when thepressurefalls. A bellcrank levert transmits the motion of the pis'- tonto the belt-shifting fork, so as to bring into action either the open orthe crossed belt upon the counter-shaft w, thereby revolving this lattereither forward or backward. This counter-shaft drives the spindle u forshifting the fork upon the cone-pulleyv, and thereby effects thereversing of the air-[laps q' q2 Q3- pulley U the speed of the entiresystem may be regulated. The forwardand-backward motion of thecounter-shaft w communicating motion to the air-flaps q enables theselatter to be operated alternately. They are so vcoupled one with anotherand also with the operating mechanism as to close the one after theother and also to open inthe same manner.

The grate consists of two link chains w, guided at the sides, whichcarry the whole grate upon distance-bars of round iron. The re-bars yare hung onto these distance-bars one against the other, so as to form agrate of the required width. The heads of the tirebars are formed withhook-shaped ears, the ends of which project only so far as to preventthe barsjfrom slipping oif in a horizontal position, but allowing thesame to be removed at the bend of the chain duringworking. The movableparts are driven from a transmission-gear with adjustment by means oftwo cone pulleys and belts and worms or gear-wheels. The lowermostair-hap is fur- By thus shifting the belt upon the conenished with aworn-sector,wl1ereby the stroke' of the aps is limited.

The sides, roof, and arches for conducting -the gases into the boilerare made of refractory material and the whole arrangement is mountedupon an iron frame, so as to allow of the same being pushed back whenclean-- ing the boiler.

Having now particularly described and ascertained the nature of my saidinvention and the manner in which the same is to be performed, I declarethat what I claim is- 1. In a mechanical stoker, the combination .withat chain grate having two surfaces inclined in an opposite direction,the Vforemost `of which is protected against air passing and openingsaidA flaps, substantially as de` scribed.

3. In a mechanical stoker, the combination with a chain grate having twosurfaces inclined in an opposite direction, the foremost of which isprotected against air passing through it, of a flue leading from thevrearend of the grate to the front end of the same, of air-flaps arrangedbelow the rear part of the grate', and of al steam-accumulatorv providedwith a counterpoise and operated by the variations of the pressure Lof asteam-generator fired by the said stoker in such a manner as to closemore or less the said air-flapsand the inlet-passagers for the "fuel,substantially as described. y

4. In a mechanical stoker, the combination with a chain grate having twosurfaces inclined in an opposite direction, the foremost of which isprotected against air passing through it, of a ue leading from the rearend of the grate to the front end of the same, and of fire-bars, theheads of which are formed in the shape of hooks,su bstantially asdescribed.

In witness whereofI hereunto subscribe my name 'this 27th day of June',A. D. 1900.

ALFRED HFMANN.

Witnesses:

A. M. LIEBERKNECHT, JEAN GRoss.

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